Current data indicates the heterogeneity of lymphocytes in the regional draining lymph nodes of rabbits undergoing acute dendritic keratitis as well as deep stromal keratitis. This heterogeneity is reflected in day to day shifts of the response of regional lymph node lymphocytes to the mitogens PHA, Con A and PWM as well as specific Herpes antigens. Lymph node populations which were separated on the basis of density in bovine serum albumin gradients also were observed to possess differential responses to mitogens as well as specific Herpes antigens. Further characterization of this heterogeneity of lymphocytes will be investigated by additional functional assays of cell mediated immunity as well as the investigation of certain surface characteristics of lymphocytes (Fc receptors, surface Ig and theta antigen density). A small anti-inflammatory polypeptide isolated from human plasma will be investigated. This polypeptide has been reported to decrease PMN chemotaxis; it will be studied in relationship to deep stromal necrotizing keratitis and the concomitant heavy influx of PMN's which has been observed histologically. Current investigations will also include further characterization of the mechanism of the local immune ring and corneal memory.